Passivation layer, preparation method thereof and perovskite solar cell

Abstract

The invention belongs to the photovoltaic field, and particularly relates to a passivation layer, a preparation method thereof and a perovskite solar cell. The passivation layer comprises the gold-platinum nano-alloy modified by the single-stranded nucleic acid molecules, so that uncoordinated Pb < 2 + > and halogen vacancies can be effectively passivated, the interface defect density is reduced, and the performance of the perovskite solar cell is improved.

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaics, and in particular relates to a passivation layer, a preparation method thereof, and a perovskite solar cell. Background Art

[0002] Organometallic halide perovskites have attracted widespread attention as next-generation photovoltaic materials due to their excellent photovoltaic performance and high cost-performance. However, in perovskite solar cells, even in high-quality polycrystalline perovskite films, a large number of surface defects, such as halide vacancies, cation vacancies, interstitial iodides, and Pb-I antisites, can still be found. Therefore, improving the quality of perovskite films, optimizing band matching, and reducing mismatched defects are effective approaches to enhance their performance. Summary of the Invention

[0003] In order to solve the problems existing in the existing technology and reduce surface defects, the present invention designs a nucleic acid-modified gold-platinum nanoalloy passivation perovskite surface, which realizes the improvement of the efficient and stable performance of perovskite solar cells through a multi-level synergistic mechanism, especially improving the fill factor and open-circuit voltage of perovskite solar cells.

[0004] Specifically, the present invention provides a passivation layer, which comprises nucleic acid / gold-platinum nanoalloy, wherein the nucleic acid / gold-platinum nanoalloy is a gold-platinum nanoalloy modified with a single-stranded nucleic acid molecule.

[0005] In one or more embodiments, the passivation layer has a thickness of 5-20 nm.

[0006] In one or more embodiments, in the nucleic acid / gold-platinum nanoalloy, the mass fraction of single-stranded nucleic acid molecules in the nucleic acid / gold-platinum nanoalloy is 5-10%, and the mass fraction of gold-platinum nanoalloy in the nucleic acid / gold-platinum nanoalloy is 90-95%.

[0007] In one or more embodiments, the gold-platinum nanoalloy has a particle size of 5-15 nm.

[0008] In one or more embodiments, in the gold-platinum nanoalloy, the mass fraction of gold in the gold-platinum nanoalloy is 70-80%, and the mass fraction of platinum in the gold-platinum nanoalloy is 20-30%.

[0009] In one or more embodiments, the single-stranded nucleic acid molecule has a length of 10-50 bp.

[0010] In one or more embodiments, in the single-stranded nucleic acid molecule, adenine accounts for 20%-30% of the total bases, guanine accounts for 30%-40% of the total bases, and cytosine accounts for 20%-30% of the total bases.

[0011] In one or more embodiments, the single-stranded nucleic acid molecule is a single-stranded DNA molecule.

[0012] In one or more embodiments, in the single-stranded DNA molecule, the amount of thymine accounts for 10%-30% of the total number of bases.

[0013] In one or more embodiments, the sequence of the single-stranded DNA molecule is selected from

[0014] 10 bp 5'-SH-GACGTGACGT-3',

[0015] 15bp 5'-SH-AGGTCAGTCGATGCT-3',

[0016] 20bp 5'-SH-GCAGTACGTGACGTGACTGC-3',

[0017] 25bp 5'-SH-GGACAGCGTGACTAGCTACGTCGAC-3',

[0018] 30bp 5'-SH-(CH2)6-AGG CAG TGA GGC ATC GAC TGG CGA TGA CCT-3',

[0019] 40bp 5'-SH-GGCAGTCAGTACGTGACTAGCTACGTGACGTGACTAGCTACGT-3' and

[0020] One or more of 50 bp 5'-SH-GGACGTGACTAGCTACGTGACGTGACTAGCTACGTGACGTGACTAGC TACGTGAC-3'.

[0021] Another aspect of the present invention provides a method for preparing the passivation layer described in any embodiment of the present invention, the method comprising dispersing a single-stranded nucleic acid molecule, a gold-platinum nanoalloy and a reducing agent in a first solvent to obtain a reaction solution, reacting, settling and washing to obtain the nucleic acid / gold-platinum nanoalloy, dispersing the nucleic acid / gold-platinum nanoalloy in a second solvent to obtain a passivation layer solution, applying the passivation layer solution, and then annealing to obtain a passivation layer.

[0022] In one or more embodiments, in the reaction solution, the mass of the single-stranded nucleic acid molecule is 0.05-0.2 mg per milliliter of the first solvent.

[0023] In one or more embodiments, in the reaction solution, the mass of the gold-platinum nanoalloy is 1-5 mg per milliliter of the first solvent.

[0024] In one or more embodiments, in the reaction solution, the mass of the reducing agent is 0.02-0.1 mg per milliliter of the first solvent.

[0025] In one or more embodiments, the reducing agent is one or more of tris(2-carboxyethyl)phosphine solution, dithiothreitol, sodium borohydride, sodium citrate, ascorbic acid, and potassium tartrate.

[0026] In one or more embodiments, the first solvent is a buffered saline solution.

[0027] In one or more embodiments, the first solvent is a PBS buffer solution.

[0028] The reaction was shaken at room temperature for 20-120 min;

[0029] In one or more embodiments, the second solvent is an alcohol solvent, and the alcohol solvent is one or more of ethanol, isopropanol, n-butanol, and n-pentanol.

[0030] In one or more embodiments, in the passivation layer solution, the mass of the nucleic acid / gold-platinum nanoalloy is 0.5-5 mg per milliliter of the second solvent.

[0031] In one or more embodiments, the coating is one or more selected from spin coating, knife coating, spray coating, slot coating, and inkjet printing.

[0032] In one or more embodiments, the annealing temperature is 80-100°C.

[0033] In one or more embodiments, the annealing time is 5-10 minutes.

[0034] Another aspect of the present invention further provides a perovskite solar cell, which comprises the passivation layer according to any embodiment of the present invention.

[0035] In one or more embodiments, the perovskite solar cell further comprises a perovskite layer and an electron transport layer, and the passivation layer is located between the perovskite layer and the electron transport layer.

[0036] The present invention designs a nucleic acid-modified gold-platinum nanoalloy passivated perovskite surface, which achieves the improvement of the efficient and stable performance of perovskite solar cells through a multi-level synergistic mechanism to obtain high-efficiency solar cells. Specifically, the technical solution of the present invention significantly improves the photoelectric conversion efficiency of perovskite solar cells from 17% to 24.3%, the fill factor is increased by 10.9%, and the open-circuit voltage is increased by 130mA. The T80 life at 85°C / 85% RH is extended from 180 hours to 900 hours. This noble metal-biomolecule hybrid strategy not only solves the contradiction between the stability and process compatibility of traditional passivation materials, but also provides an innovative solution for the industrialization of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Figure 1 shows the structure of an inverse perovskite solar cell in some embodiments. Here, 1 is a transparent electrode layer; 2 is a hole transport layer; 3 is a perovskite light-absorbing layer; 4 is a passivation layer; 42 is a nucleic acid / gold-platinum nanoalloy particle; 5 is an electron transport layer; and 6 is a metal electrode layer. DETAILED DESCRIPTION

[0038] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0039] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0040] Herein, “comprising,” “including,” “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of,” for example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to have been disclosed herein.

[0041] Throughout this document, all features, such as values, amounts, amounts, and concentrations, specified in numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to encompass and specifically disclose all possible subranges and individual values ​​within those ranges (including integers and fractions).

[0042] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0043] Herein, when describing embodiments or examples, it should be understood that they are not intended to limit the present invention to these embodiments or examples. On the contrary, all alternatives, modifications and equivalents of the methods and materials described herein are encompassed within the scope defined by the claims.

[0044] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0045] The present invention provides a passivation layer comprising nucleic acid / gold-platinum nanoalloy, wherein the nucleic acid / gold-platinum nanoalloy is a gold-platinum nanoalloy modified with a single-stranded nucleic acid molecule.

[0046] In the present invention, the thickness of the passivation layer is 5-20 nm, for example, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, and 19 nm.

[0047] In the present invention, the mass fraction of the single-stranded nucleic acid molecule in the nucleic acid / gold-platinum nanoalloy is 5-10%, for example, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%; when the mass fraction of the single-stranded nucleic acid molecule in the nucleic acid / gold-platinum nanoalloy is too high (greater than 10%), its conductivity will be reduced, and when its mass fraction is too low (<5%), the passivation ability of the nucleic acid / gold-platinum nanoalloy will be insufficient. Controlling the single-stranded nucleic acid molecule within the above mass fraction is beneficial to taking into account the conductivity and passivation ability of the nucleic acid / gold-platinum nanoalloy as a passivation layer material; in particular, in some preferred embodiments, using single-stranded DNA and gold-platinum nanoalloy for compounding, and controlling the mass fraction of the single-stranded DNA in 5-10% can effectively passivate the surface defects of the perovskite (such as Pb 2 + vacancies), while maintaining the charge transport capability of the nanoalloy; the mass fraction of the gold-platinum nanoalloy in the nucleic acid / gold-platinum nanoalloy is 90-95%, such as 90.5%, 91%, 91.5%, 92%, 92.5%, 93%, 94%, 94.5%; the nanoalloy as the main body needs to provide a conductive network and light stability. When the mass fraction of the gold-platinum nanoalloy is too high (>95%), it will lead to insufficient passivation. When the mass fraction of the gold-platinum nanoalloy is too low (<90%), it will affect the charge collection efficiency. Wherein, the particle size of the gold-platinum nanoalloy is generally 5-15nm, such as 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm.

[0048] In the present invention, the mass fraction of gold in the gold-platinum nanoalloy is 70-80%, for example, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%. Controlling the mass fraction of gold within the above range is beneficial to ensuring high conductivity and surface plasma effect of the passivation material and enhancing light absorption; the mass fraction of platinum in the gold-platinum nanoalloy is 20-30%, for example, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%. Controlling the mass fraction of platinum within the above range is beneficial to catalyzing the passivation layer. The charge transfer at the perovskite interface inhibits the migration of iodide ions. When the platinum content is too high (>30%), agglomeration may occur. At the same time, controlling the mass fractions of gold and platinum within the above-mentioned ranges can control costs and facilitate the synergistic enhancement of light absorption by the localized surface plasmon resonance (500-600nm) of gold and the near-infrared response of platinum, thereby improving the short-circuit current density of the perovskite photovoltaic module containing the passivation layer of the present invention. In particular, the catalytic effect of Pt decomposes H2O / O2, which can extend the T80 life of the perovskite photovoltaic module containing the passivation layer of the present invention.

[0049] In the present invention, the length of the single-stranded nucleic acid molecule is 10-50 bp, for example, 10 bp, 15 bp, 20 bp, 25 bp, 30 bp, 40 bp, or 50 bp.

[0050] In the single-stranded nucleic acid molecule of the present invention, adenine (A) accounts for 20%-30% of the total bases, guanine (G) accounts for 30%-40% of the total bases, and cytosine (C) accounts for 20%-30% of the total bases. Controlling the ratio of each base within the above range is beneficial to improving the passivation ability of the passivation layer of the present invention.

[0051] In some embodiments, the single-stranded nucleic acid molecule is ssDNA, wherein the amount of thymine preferably accounts for 10%-30% of the total number of bases, more preferably 10%-15%. Controlling the amount of thymine within the above ratio is beneficial to the passivation ability of the passivation layer of the present invention.

[0052] The present invention provides a method for preparing a passivation layer: a single-stranded nucleic acid molecule, a gold-platinum nanoalloy and a reducing agent are dispersed in a first solvent (such as PBS buffer) to obtain a reaction solution; the reaction solution is reacted, statically precipitated and washed to obtain a nucleic acid / gold-platinum nanoalloy; the nucleic acid / gold-platinum nanoalloy is dispersed in a second solvent to obtain a passivation layer solution; the passivation layer solution is applied, and then annealed to obtain a passivation layer.

[0053] In the reaction solution:

[0054] Relative to each milliliter of the first solvent, the mass of the single-stranded nucleic acid molecule is 0.05-0.2 mg (for example, 0.06 mg, 0.07 mg, 0.08 mg, 0.09 mg, 0.1 mg, 0.11 mg, 0.12 mg, 0.13 mg, 0.14 mg, 0.15 mg, 0.16 mg, 0.17 mg, 0.18 mg, 0.19 mg); relative to each milliliter of the first solvent, the mass of the gold-platinum nanoalloy is 1-5 mg (for example, 1.5 mg, 2 mg, 2.5 mg, 3 mg, 3.5 mg, 4 mg, 4.5 mg); relative to each milliliter of the first solvent, the mass of the reducing agent (for example, TCEP) is 0.02-0.1 mg (for example, 0.03 mg, 0.04 mg, 0.05 mg, 0.06 mg, 0.07 mg, 0.08 mg, 0.09 mg).

[0055] The reaction conditions for the reaction between the single-stranded nucleic acid molecule, the gold-platinum nanoalloy and the reducing agent are:

[0056] Shake at room temperature for 20-120 min (e.g., 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min, 100 min, 105 min, 110 min, 115 min), and let stand for 10-30 min (e.g., 15 min, 20 min, 25 min).

[0057] In the passivation layer solution of the present invention, the mass of the nucleic acid / gold-platinum nanoalloy per milliliter of the second solvent is 0.5-5 mg, for example, 1 mg, 1.5 mg, 2 mg, 2.5 mg, 3 mg, 3.5 mg, 4 mg, or 4.5 mg.

[0058] In the present invention, the coating method can be one or more of spin coating, blade coating, spray coating, slit coating and inkjet printing.

[0059] In the present invention, the annealing temperature may be 80-100° C., such as 85° C., 90° C., or 95° C.; and the annealing time may be 5-10 min, such as 6 min, 7 min, 8 min, or 9 min.

[0060] In some embodiments, the present invention utilizes a low-temperature (80°C-100°C, e.g., 85°C, 90°C, 95°C) spin-coating / inkjet printing process to prepare the passivation layer, thereby maintaining large-area uniformity of perovskite photovoltaic modules. By incorporating a metal-biomolecule hybrid strategy into the passivation layer, the present invention effectively addresses the conflict between stability and process compatibility of traditional passivation materials, providing an innovative solution for the industrialization of perovskite solar cells.

[0061] In the present invention, the raw materials of the perovskite structure material can be AX and BX2, and the A ion is a monovalent cation, including but not limited to cesium ions (Cs + ), rubidium ions (Rb + ), methylamine ion (CH3NH3 + , MA + ) and formamidinium ion (CH(NH2)2 + , FA + ) one or more; B ions are divalent cations, including but not limited to lead ions (Pb 2+ ) and / or tin ions (Sn 2+ ); X ion is a monovalent anion, which may include but is not limited to iodide ion (I - ), bromide ion (Br - ) and chloride ions (Cl - ); preferably, in the raw materials for the perovskite structure material, the A ion is selected from one or more of a cesium ion, a methylamine ion, and a formamidine ion; the B ion is a lead ion; and the X ion is an iodide ion and / or a bromide ion. Using the preferred raw materials for the perovskite structure material facilitates the preparation of a ternary mixed organic halogen hybrid perovskite structure material, which has the greatest commercial prospects in terms of optoelectronic parameters and stability.

[0062] In some embodiments, the perovskite structure material is CsFAPbI3, MAPbI3, CsPbI3 and Cs x FA 1-x Pb(I y Br 1-y )3.

[0063] The electron transport layer of the present invention can be selected from n-type single crystal silicon, n-type polycrystalline silicon, n-type amorphous silicon, TiO2, SnO2, ZnO, ZrO2, GZO, IZO, FTO, ITO, BaSnO3, TiSnO x 、SnZnO x , one or more of fullerenes (such as C60 and C70) and fullerene derivatives (such as PCBM).

[0064] The electrode material of the present invention can be one or more selected from Au, Ag, Al, Cu, graphene, TCO materials and nanocrystalline silicon, and the electrode preparation method includes but is not limited to one or more of spin coating, blade coating, evaporation, printing, spraying, spray pyrolysis and slit coating.

[0065] The present invention provides a perovskite solar cell comprising a passivation layer of the present invention. In the present invention, the perovskite solar cell may include a single-junction perovskite solar cell or a tandem perovskite solar cell; the perovskite solar cell may include a formal perovskite solar cell (NIP-type perovskite solar cell) or an inverted perovskite solar cell (PIN-type perovskite solar cell). Specifically, the perovskite solar cell may be a formal single-junction perovskite solar cell, an inverted single-junction perovskite solar cell, or a tandem perovskite solar cell.

[0066] In some embodiments, the perovskite solar cell of the present invention is Figure 1 shown.

[0067] In some embodiments, the perovskite solar cell of the present invention can be prepared by the following method:

[0068] (1) Using magnetron sputtering to prepare an ITO transparent electrode or FTO transparent electrode with a thickness of 100 nm;

[0069] (2) A NiOx hole transport layer with a thickness of 15 nm was prepared by magnetron sputtering or a PTAA or PEDOT / PSS hole transport layer with a thickness of 10 nm was prepared by blade coating.

[0070] (3) The active material is CsFAPbI3, MAPbI3, CsPbI3 or CsxFA prepared by slit coating or wire rod coating 1-x Pb(I y Br 1-y )3 perovskite layer; the annealing temperature used is 120-160°C; the thickness is preferably 300-600nm.

[0071] (4) Prepare the passivation layer by scraping or coating: scrape 0.5-5 mg / mL nucleic acid / gold platinum nanoalloy particle solution (solvent is isopropanol) on the surface of the perovskite film, and then anneal at 80-100 ° C for 10 min to a thickness of 5-10 nm.

[0072] (5) Electron transport layer and buffer layer were prepared by vacuum evaporation: 15nm C60 / 6nm bathocuproin (BCP);

[0073] (6) Copper, aluminum, silver or gold electrodes with a thickness of 90-200 nm are prepared by vacuum evaporation.

[0074] The present invention will be described below by way of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents, and materials used in the examples are, unless otherwise stated, conventional methods, reagents, and materials in the art. The starting compounds in the examples can all be purchased from commercial sources.

[0075] The raw materials used in the synthesis of the present invention were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. and Nanjing GenScript Biotechnology Co., Ltd.

[0076] The key instruments used in the present invention include but are not limited to a calibrated temperature and humidity chamber, a solar simulator (Class AAA) and an IV tester.

[0077] Preparation Example

[0078] (1) 10 mg of H2PtCl6·6H2O and 30 mg of HAuCl4·4H2O were placed in PBS buffer solution at pH = 7.4 and stirred at room temperature for 0.5 h to dissolve all the above materials. Then, 5 mL of NaBH4 (5 mg / mL) was added dropwise to the above reaction system and stirred for 6 h. The solid was collected by centrifugation and washed three times with ethanol and water respectively. After drying, 20 mg of gold-platinum nanoalloy with a particle size of 10 nm was obtained.

[0079] (2) A centrifuge tube containing 2 mg of ssDNA (synthesized by Nanjing GenScript Biotechnology Co., Ltd., with a nucleic acid sequence of 5'-SH-(CH2)6-AGG CAG TGA GGC ATC GAC TGG CGA TGA CCT-3') was run at 20,000 rpm to allow the nucleic acid sample to precipitate at the bottom of the centrifuge tube. A PBS buffer solution with a pH of 7.4 was added and the solution was shaken at room temperature to dissolve the solution. Then, 50 mM tris(2-carboxyethyl)phosphine solution (TCEP) was added and the solution was shaken at room temperature for 1 hour. Then, 10 mg of the gold-platinum nanoalloy prepared in step (1) was added and the solution was shaken at room temperature for 20 minutes. The solution was then allowed to stand for 30 minutes to allow the nucleic acid and the gold-platinum nanoparticles to be connected through Au-S bonds. The nucleic acid / gold-platinum nanoalloy solution was then centrifuged and washed. The precipitate was washed with deionized water and isopropyl alcohol (IPA), respectively. After washing three times each, 8 mg of pure nucleic acid / gold-platinum nanoalloy particles were obtained, wherein the mass fraction of the nucleic acid was 10% and the mass fraction of the gold-platinum nanoalloy particles was 90%.

[0080] (3) The nucleic acid / gold-platinum nanoalloy particles prepared in step (2) were redispersed in IPA to prepare nucleic acid / gold-platinum nanoalloy solutions of different concentrations (0.5 mg / mL, 2.5 mg / mL, 5 mg / mL), which were stored at 4°C in the dark for later use.

[0081] Example 1

[0082] like Figure 1 As shown, an inverted perovskite solar cell is prepared in the order of FTO transparent electrode, hole transport layer, perovskite layer, passivation layer, electron transport layer and metal electrode. The specific steps are as follows:

[0083] (1) A 100 nm thick FTO transparent electrode was prepared by magnetron sputtering.

[0084] (2) NiO with a thickness of 15 nm was prepared on the surface of the transparent electrode by magnetron sputtering x hole transport layer;

[0085] (3) A 460 nm thick perovskite layer was prepared on the surface of the hole transport layer by wire rod coating: 1.8 M FAPbI3 was prepared and dissolved in N,N-dimethylformamide (DMF) / N-methylpyrrolidone (NMP) (v:v = 18:2) solvent, and the coating was performed at a coating rate of 5 mm / s. The excess solvent was then blown away with a nitrogen gun until the surface of the perovskite film turned dark yellow, and then annealed at 100 °C for 15 min.

[0086] (4) A passivation layer was prepared on the surface of the perovskite layer by scraping at a scraping rate of 15 mm / s and a liquid injection rate of 20 μL / s. 200 μL of a 0.5 mg / mL nucleic acid / gold-platinum nanoalloy solution (Preparation Example 1) was scraped onto the surface of the perovskite film at 5 seconds, followed by annealing at 100°C for 10 min.

[0087] (5) The electron transport layer is prepared on the surface of the passivation layer by vacuum evaporation: 15nm C60 / 6nm BCP;

[0088] (6) A silver electrode with a thickness of 150 nm was prepared on the surface of the electron transport layer by vacuum evaporation.

[0089] Example 2

[0090] The other conditions of this embodiment are the same as those of Example 1, except that the concentration of the nucleic acid / gold-platinum nanoalloy solution used in this embodiment is 2.5 mg / ml.

[0091] Example 3

[0092] The other conditions of this embodiment are the same as those of Example 1, except that the concentration of the nucleic acid / gold-platinum nanoalloy solution used in this embodiment is 5 mg / ml.

[0093] Example 4

[0094] The other conditions of this embodiment are the same as those of embodiment 1, with the only difference being that the particle size of the gold-platinum nanoalloy in this embodiment is 5 nm.

[0095] Example 5

[0096] Other conditions of this embodiment are the same as those of embodiment 1, with the only difference being that the particle size of the gold-platinum nanoalloy in this embodiment is 15 nm.

[0097] Comparative Example 1

[0098] The other conditions of this comparative example 1 are the same as those of Example 1, except that the passivation layer of this comparative example adopts a 0.5 mg / mL nucleic acid solution (with IPA as the solvent).

[0099] Comparative Example 2

[0100] The other conditions of this comparative example 1 are the same as those of Example 1, except that the passivation layer of this comparative example adopts a 0.5 mg / mL nucleic acid / gold solution (with IPA as the solvent), wherein the gold particle size is 10 nm.

[0101] Comparative Example 3

[0102] Other conditions of this comparative example 1 are the same as those of Example 1, except that the passivation layer of this comparative example adopts a 0.5 mg / mL nucleic acid / platinum solution (with IPA as the solvent), wherein the particle size of platinum is 10 nm.

[0103] Test Case

[0104] 1. At 25°C, AM 1.5G standard solar spectrum, light intensity of 1000mW / cm 2 Under the conditions of 1 sun intensity, a solar simulator was used with the voltage range set to -0.2-1.3 V and a scan rate of 50 mV / s to measure the performance (open circuit voltage, short circuit current density, fill factor, and photoelectric conversion efficiency) of the solar cell modules in Examples 1-5 and Comparative Examples 1-3. The specific results are shown in Table 1.

[0105] (1) Open circuit voltage (Voc): The voltage value corresponding to the current being zero.

[0106] (2) Short-circuit current density (Jsc): The current value when the voltage is zero is the short-circuit current (Isc), and the current per unit battery surface area is the short-circuit current density.

[0107] (3) Fill factor (FF): The ratio of the maximum output power (Pmax) of the battery to the product of the open circuit voltage and the short circuit current. The calculation formula is (Pmax / Voc*Isc), where the maximum power point is the point where the battery output power reaches its maximum value.

[0108] (4) Photoelectric conversion efficiency (PCE): Photoelectric conversion efficiency refers to the ratio of maximum output power to incident light power (Pin), and the calculation formula is (Pmax / Pin)*100%.

[0109] 2. The specific results of the T80 lifetime of Examples 1-5 and Comparative Examples 1-3 measured at 85°C / 85% RH are shown in Table 1. The specific testing method is to place the perovskite solar cells of Examples 1-5 and Comparative Examples 1-3 in a constant temperature and humidity chamber (85±2°C / 85±5% RH), continuously age them in the dark, and measure the PCE every 24 hours after cooling to 25°C. The cumulative time (T80 lifetime) is recorded until the efficiency drops to 80% of the initial value. During the test, ensure that the sample spacing is ≥5cm. Set up three parallel groups for each example and take the average measurement value.

[0110] Table 1: Photovoltaic performance test results of solar cell modules of Examples 1-5 and Comparative Examples 1-3

[0111]

[0112] Table 1 shows the effect of particle size on passivation. When the gold-platinum nanoparticle alloy has a particle size of 10 nm (Examples 1-3), the PCE of the corresponding solar cell module decreases with increasing gold-platinum nanoparticle alloy concentration (23.9% → 22.3%), but is generally higher than that of Comparative Examples 2-3, which only have a single metal (gold or platinum) added to the passivation layer. This indicates that the gold-platinum nanoalloy with a particle size of 10 nm has the ability to effectively passivate nucleic acids. The solar cell module of Example 4 (gold-platinum nanoalloy with a particle size of 5 nm) has the highest PCE (24.3%). This is because when the gold-platinum nanoalloy has a smaller particle size, it can be more densely covered with perovskite surface defects after being complexed with nucleic acids, enhancing charge extraction. However, the PCE of the solar cell module of Example 5 (the particle size of the gold-platinum nanoalloy is 15 nm) is slightly lower (23.5%) than that of Examples 1 and 4. This may be because the increase in the particle size of the gold-platinum nanoalloy leads to a decrease in the contact area between the passivation layer formed after the complex with the nucleic acid and the interface with the perovskite layer, or leads to insufficient coverage of some interface areas.

[0113] Table 1 also shows the synergistic relationship between concentration and particle size. When the AuPt nanoalloy particle size was 10 nm and the concentration of the nucleic acid / AuPt nanoalloy in the passivation layer was 0.5 mg / mL, the PCE was optimal, at 23.9%. When the concentration of the nucleic acid / AuPt nanoalloy in the passivation layer was 0.5 mg / mL and the AuPt nanoalloy particle size was 5 nm, the PCE of the solar cell module was optimal, at 24.3%. This indicates that the low-particle AuPt nanoalloy combined with nucleic acid and then added to the passivation layer with a low concentration of nucleic acid / AuPt nanoalloy exhibited superior passivation. However, when the AuPt nanoalloy particle size was 10 nm and the concentration of nucleic acid / AuPt nanoalloy was 5 mg / mL, the PCE of the solar cell module decreased to only 22.3%. This may be due to the high concentration causing agglomeration of the nucleic acid / AuPt nanoalloy particles or exacerbating interfacial recombination, which in turn affected the passivation effect and electrochemical performance.

[0114] Finally, Comparative Examples 2 (nucleic acid / nano-gold) and 3 (nucleic acid / nano-platinum) in Table 1 demonstrate the limitations of using a single metal in combination with nucleic acid to prepare a passivation layer. Although the PCE of Comparative Examples 2 and 3 also increased by 2.38%-3.05% compared to Comparative Example 1 (adding pure nucleic acid to the passivation layer), it is still far lower than that of the nucleic acid / gold-platinum nano-alloy after being combined with gold-platinum nano-alloy. This indicates that the addition of gold-platinum nano-alloy and nucleic acid has a synergistic effect on the performance improvement of the prepared passivation layer and its solar cell module. This may be because the synergistic effect of the gold-platinum alloy enhances the electron transport capacity of the solar cell module and passivates the surface defects of the perovskite layer.

Claims

1. A passivation layer, characterized in that: The passivation layer comprises nucleic acid / gold-platinum nanoalloy, and the nucleic acid / gold-platinum nanoalloy is a gold-platinum nanoalloy modified with a single-stranded nucleic acid molecule.

2. The passivation layer according to claim 1, wherein The passivation layer has one or more of the following characteristics: The thickness of the passivation layer is 5-20 nm; In the nucleic acid / gold-platinum nanoalloy, the mass fraction of the single-stranded nucleic acid molecule in the nucleic acid / gold-platinum nanoalloy is 5-10%, and the mass fraction of the gold-platinum nanoalloy in the nucleic acid / gold-platinum nanoalloy is 90-95%; The particle size of the gold-platinum nanoalloy is 5-15 nm; In the gold-platinum nano alloy, the mass fraction of gold in the gold-platinum nano alloy is 70-80%, and the mass fraction of platinum in the gold-platinum nano alloy is 20-30%.

3. The passivation layer according to claim 1, wherein The length of the single-stranded nucleic acid molecule is 10-50 bp; and / or In the single-stranded nucleic acid molecule, adenine accounts for 20%-30% of the total bases, guanine accounts for 30%-40% of the total bases, and cytosine accounts for 20%-30% of the total bases.

4. The passivation layer according to claim 1, wherein The single-stranded nucleic acid molecule is a single-stranded DNA molecule. Preferably, in the single-stranded DNA molecule, the amount of thymine accounts for 10%-30% of the total number of bases.

5. The passivation layer according to claim 4, wherein The sequence of the single-stranded DNA molecule is selected from 10 bp 5'-SH-GACGTGACGT-3', 15bp 5'-SH-AGGTCAGTCGATGCT-3', 20bp 5'-SH-GCAGTACGTGACGTGACTGC-3', 25bp 5'-SH-GGACAGCGTGACTAGCTACGTCGAC-3', 30bp 5'-SH-(CH2)6-AGG CAG TGA GGC ATC GAC TGG CGA TGA CCT-3', 40bp 5'-SH-GGCAGTCAGTACGTGACTAGCTACGTGACGTGACTAGCTACGT-3' and One or more of 50 bp 5'-SH-GGACGTGACTAGCTACGTGACGTGACTAGCTACGTGACGTGACTAGC TACGTGAC-3'.

6. A method for preparing the passivation layer according to any one of claims 1 to 5, characterized in that: The method comprises dispersing a single-stranded nucleic acid molecule, a gold-platinum nanoalloy and a reducing agent in a first solvent to obtain a reaction solution, performing reaction, static precipitation and washing to obtain the nucleic acid / gold-platinum nanoalloy, dispersing the nucleic acid / gold-platinum nanoalloy in a second solvent to obtain a passivation layer solution, coating the passivation layer solution, and then annealing to obtain a passivation layer.

7. The method according to claim 6, wherein The method has one or more of the following characteristics: In the reaction solution, the mass of the single-stranded nucleic acid molecule is 0.05-0.2 mg per milliliter of the first solvent; In the reaction solution, the mass of the gold-platinum nanoalloy is 1-5 mg per milliliter of the first solvent; In the reaction solution, the mass of the reducing agent is 0.02-0.1 mg per milliliter of the first solvent; The reducing agent is one or more of tris(2-carboxyethyl)phosphine solution, dithiothreitol, sodium borohydride, sodium citrate, ascorbic acid and potassium tartrate; The first solvent is a buffered saline solution, preferably a PBS buffer solution; The reaction was shaken at room temperature for 20-120 min; The second solvent is an alcohol solvent, and the alcohol solvent is one or more of ethanol, isopropanol, n-butanol and n-pentanol; In the passivation layer solution, the mass of the nucleic acid / gold-platinum nanoalloy is 0.5-5 mg per milliliter of the second solvent.

8. The method according to claim 6, wherein The method has one or more of the following characteristics: The coating is one or more selected from spin coating, blade coating, spray coating, slit coating and inkjet printing; The annealing temperature is 80-100° C. The annealing time is 5-10 minutes.

9. A perovskite solar cell comprising the passivation layer according to any one of claims 1 to 5.

10. The perovskite solar cell according to claim 9, wherein The perovskite solar cell further comprises a perovskite layer and an electron transport layer, and the passivation layer is located between the perovskite layer and the electron transport layer.

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